ESTIMATING AND FORECASTING THE SMOKING-ATTRIBUTABLE MORTALITY FRACTION FOR BOTH GENDERS JOINTLY IN OVER 60 COUNTRIES

Accounting for Smoking in Forecasting Mortality and Life Expectancy

Smoking is one of the main risk factors that has affected human mortality and life expectancy over the past century. Smoking accounts for a large part of the nonlinearities in the growth of life expectancy and of the geographic and sex differences in mortality. As Bongaarts (2006) and Janssen (2018) suggested, accounting for smoking could improve the quality of mortality forecasts due to the predictable nature of the smoking epidemic. We propose a new Bayesian hierarchical model to forecast life expectancy at birth for both sexes and for 69 countries with good data on smoking-related mortality. The main idea is to convert the forecast of the non-smoking life expectancy at birth (i.e., life expectancy at birth removing the smoking effect) into life expectancy forecast through the use of the age-specific smoking attributable fraction (ASSAF). We introduce a new age-cohort model for the ASSAF and a Bayesian hierarchical model for non-smoking life expectancy at birth. The forecast performance of the proposed method is evaluated by out-of-sample validation compared with four other commonly used methods for life expectancy forecasting. Improvements in forecast accuracy and model calibration based on the new method are observed.

Estimating future smoking in Danish youth – effects of three prevention strategies

Aims: Preventing smoking and aiding cessation among youth and young adults carries the possibility of reducing future smoking prevalence significantly. This paper estimates the impact on future smoking prevalence of 25 year olds by increasing tobacco prices, securing indoor smoke-free homes and implementing school-based multi-tiered interventions. Methods: Utilizing a multi-state Markov model, a status quo projection of the smoking prevalence from years 2017 to 2030 were compared with projections of the smoking prevalence in 2030 considering the impact of the three prevention strategies. Results: In a status quo projection, 27.0% of Danish 25-year-old females are expected to be smokers in 2030, while 13.2% would be smokers in 2030 were all three prevention strategies in effect from 2019. By itself, increasing tobacco prices by 50% reduced the prevalence of smokers among 25-year-old females to 14.8% in 2030, a relative reduction of 47.5%. For 25-year-old males in 2030 the reductions were similar, with a prevalence of 16.6% when all three prevention strategies were in effect, a relative reduction of 51.5%. Conclusions: Implementing increasing tobacco prices, indoor smoke-free homes and school-based multi-tiered interventions in Denmark is likely to significantly decrease youth smoking prevalence in the future. However, these three strategies will not produce a smoke-free generation without other initiatives.

Smoking epidemic in Europe in the 21st century

OBJECTIVE

To estimate smoking-attributable mortality in the long-term future in 29 European countries using a novel data-driven forecasting approach that integrates the wave pattern of the smoking epidemic and the cohort dimension.

METHODS

We estimated and forecasted age-specific and age-standardised smoking-attributable mortality fractions (SAMF) and 95% projection intervals for 29 European countries by sex, 1950-2100, using age-period-cohort modelling with a generalised logit link function. We projected the (decelerating) period increases (women) by a quadratic curve to obtain future declines, and extrapolated the past period decline (men). In addition, we extrapolated the recent cohort trend.

RESULTS

SAMF among men are projected to decline from, on average, 25% in 2014 (11% (Sweden)-41% (Hungary)) to 11% in 2040 (range: 6.3%-15.4%), 7% in 2065 (range: 5.9%-9.4%) and 6% in 2100. SAMF among women in 21 non-Eastern European countries, currently at an average of 16%, are projected to reach peak levels in 2013 (Northern Europe), 2019 (Western Europe), 2027 (Greece, Italy) and 2022 (Central Europe), with maximum levels of, on average, 17% (8% (Greece)-28% (Denmark)), and to decline to 10% in 2040 (range: 4%-20%), 5% in 2065 (range: 3.5%-7.6%) and 4% in 2100. For women, a short-term shift in the peak of the inverse U-shaped age pattern to higher ages is projected, and crossovers between the age-specific trends.

CONCLUSION

Our novel forecasting method enabled realistic estimates of the mortality imprint of the smoking epidemic in Europe up to 2100. The high peak values in smoking-attributable mortality projected for women warrant attention.

ESTIMATING AND FORECASTING THE SMOKING-ATTRIBUTABLE MORTALITY FRACTION FOR BOTH GENDERS JOINTLY IN OVER 60 COUNTRIES

Smoking is one of the leading preventable threats to human health and a major risk factor for lung cancer, upper aero-digestive cancer, and chronic obstructive pulmonary disease. Estimating and forecasting the smoking attributable fraction (SAF) of mortality can yield insights into smoking epidemics and also provide a basis for more accurate mortality and life expectancy projection. Peto et al. (1992) proposed a method to estimate the SAF using the lung cancer mortality rate as an indicator of exposure to smoking in the population of interest. Here we use the same method to estimate the all-age SAF (ASAF) for both genders for over 60 countries. We document a strong and cross-nationally consistent pattern of the evolution of the SAF over time. We use this as the basis for a new Bayesian hierarchical model to project future male and female ASAF from over 60 countries simultaneously. This gives forecasts as well as predictive distributions that can be used to find uncertainty intervals for any quantity of interest. We assess the model using out-of-sample predictive validation, and find that it provides good forecasts and well calibrated forecast intervals, comparing favorably with other methods.